The correct answer is c) Idukki.
Graphite is a mineral that is used in a variety of products, including pencils, lubricants, and batteries. It is found in many parts of the world, including India. The largest deposits of graphite in India are located in the state of Jharkhand. However, there are also significant deposits of graphite in the state of Kerala, particularly in the district of Idukki.
The graphite deposits in Idukki are located in the Western Ghats mountain range. The graphite is found in metamorphic rocks that were formed when ancient sediments were subjected to heat and pressure. The graphite is mined from open-pit mines.
The graphite from Idukki is of high quality and is used in a variety of products, including pencils, lubricants, and batteries. The graphite industry in Idukki is an important part of the local economy.
The other options are incorrect because they do not have significant deposits of graphite.
a) Wayanad is a district in the state of Kerala. It is located in the Western Ghats mountain range. The district is known for its natural beauty and its coffee plantations. However, there are no significant deposits of graphite in Wayanad.
b) Kottayam is a district in the state of Kerala. It is located in the central part of the state. The district is known for its backwaters and its tea plantations. However, there are no significant deposits of graphite in Kottayam.
d) Ernakulam is a district in the state of Kerala. It is located in the northern part of the state. The district is known for its commercial importance and its cultural heritage. However, there are no significant deposits of graphite in Ernakulam.